Alternator intermittent output

2007 DCLB TRD sport, have been getting issues with occasional dash lights coming on (abs, park brake and diff lock symbol), and then the blower, windows and speedo stop working. It sometimes goes away in a few minutes, sometimes not. When this happens, there doesn't appear to be any alternator output.

Just changed worn brushes and rectifier on the alternator, was fine for a bit then happened again. Connections from alt to battery seem good (ohmic measured, and no voltage drop).
Last time it happened I got a cel for the vehicle speed sensor(p0500) , but that's the first time that's showed up.

Is there anything with the ecu or other wiring that would intermittently stop the alternator output like that?
I would have thought that with it turning it would just put out what they put out?

 

Sounds to me like you are having low voltage issues. I suspect that you still have internal problems with your Alternator. Pull it off and have it checked.

 

Did you turn the armature?

 

Yeah, I'm assuming it's still the alternator, but wanted to rule out any other possibilities of components that may effect alternator output, which I'm assuming is none. When working properly I get 14.2V at the battery, when get the issue, it's 12.5ish v.
Perhaps there's a broken wire internally, that's making intermittent contact....
It happens only when I start the truck, and not every time. most of the time it's running at full voltage, so it doesn't seem like a constant fluctuation. It's either at good voltage ranges, or no output. I would think dirty armature would cause more of a constant lowered output, no?

 

Had problem with 05 rav 4 exact problem but wasn't intermittent .Ended up gauge fuse was blown .Try replacing gauge and ign 2 fuse . Maybe fuse begining to fail .Usually would just fail but strange things do happen .Fuse is cheap enough .
Toyota 1 fuse has several different circuits .

 

If doesnt solve issue maybe see what if any circuit breaker might feed those fuses .

 

Hmm, but would that cause no output reading from the alternator though? I'm suspicious of it being the other way around, that the lowered voltage isn't allowing proper function of the cabin components. I'll check it out, though, thanks.

 

Check the large cable from the alternator to the battery. It is exposed and prone to degrade which increases resistance and heat and makes it fail faster. It’s a cheap and easy piece to replace.

 

I had the same low voltage from the positive alternator post with the cable removed , and no voltage drop on that cable, so I'm pretty confident it's not that.
I'm thinking I need to open the alternator up, or just get a new one.

 

If you getting 12.5 volts shouldn't affect dash warning lights .When my alternator crapped out noticed cranking slow so checked battery and was low .Replaced since was 4 years old and noticed wasn't charging . Alternator was bad at 70k miles

 

I've read of others on the forum having the dash lights come on and blower stop from low voltage, I wouldn't have thought it would happen either. I will be checking those fuses though. Thanks

 

Do the big 4

 

You may have hit it there. Pulled the ign2 fuse, it was a cheapy flimsy brand and the pin was crooked, and may not have been making good contact. Pulling it brought up the lights, and caused the low voltage condition at the battery (which seems odd to me but whatever).
New one in and all looks good. Time will tell. Cheers

 

Good to here .

 

Worn slip rings in the alternator will do this also.

 

Voltage regulators do die. In the old days they were mechanical and adjustable, now a days they are mostly solid state and internal to the alternators.